Injection molded eva foam barbell pad

ABSTRACT

Pad that mounts on the bar of a barbell and spreads forces exerted by the bar over a larger area of the shoulders, neck, and/or chest of a person upon which the bar is resting. The pad has an elongated body of resilient, highly compressible injection molded EVA foam having an annular cross section, an inner surface that grips the bar and holds the pad in place on the bar, and an outer surface with an ogee curvature that conforms to the contour of the shoulders, neck, and/or chest of the person using the barbell.

BACKGROUND OF THE INVENTION Field of Invention

This invention pertains generally to exercise and fitness equipment and, more particularly, to a pad that mounts on the bar of a barbell and spreads forces exerted by the bar over a larger area of the shoulders, neck, and/or chest of a person upon which the bar is resting.

Related Art

Barbell pads are used in performing a wide range of exercises such as knee bends or squats where the user rests a loaded barbell across his/her shoulders and back or across the chest and shoulders while performing shoulder press exercises. Such pads are typically made of some type of extruded foam material, and their main purpose is to provide cushioning between the bar and the body and thereby improve the comfort or reduce the discomfort of a barbell loaded with weight on a user's body.

The most basic type of bar pad currently available consists of a length of tubular foam which is slid over the end of a bar or formed with a slitted opening along one side which allows the pad to be installed and removed from the side of the bar without removing the weights. More elaborate pads have fabric covers with Velcro® fasteners along the slit. The fasteners hold the cover on the pad and aid somewhat in minimizing pad rotation. The cover adds an outer layer of material that provides a moderate level of protection against external damage to the foam, acts as a moisture barrier to keep the porous cell foam material from absorbing excessive perspiration, and allows the exterior of the product to be more easily cleaned.

The tubular foam bar pads currently on the market are manufactured by extrusion, and most of them have a linear shape with uniform wall thickness and cross section throughout their length. Only a few have any ergonomic shape corresponding to the contours of the human body, and those that do are generally formed initially as straight tubes, following which a secondary manufacturing operation is employed to cut away or otherwise remove material from the extruded tubes to better match the contours of the body.

Many of the bar pads currently in the marketplace are nothing more than foam pipe insulation repurposed to become bar pads by cutting the material to a desired length and slitting one side to allow the user to slip the pad onto the bar and cushion his/her back during exercise.

The materials currently used in bar pads include NBR (nitrile butadiene rubber) foam, polyethylene foam, and other open cell materials that are compatible with the extrusion process. The open cell materials typically have varying or random cell sizes, inconsistent and/or uncontrollable cell structures, and a thin outer layer or skin that is produced as a byproduct of the extrusion process and affords some limited protection to the underlying open cell structure.

The extrusion process does offer some advantages such as low manufacturing cost, good control over the final inner and outer diameters, and moderate durometer control, and extruded bar pads are generally considered to be the best compromise between function and price.

However, the foam materials and extrusion process currently in use also have a number of limitations and disadvantages in the manufacture of bar pads. The foam materials do not have a high compression life cycle, they are not resilient, and they are prone to compression setting after repeated loading and unloading. This degrades the thin outer skin and accelerates the collapse of the underlying cell structure, which leads to poor long-term durability and a rapid loss of functionality. This degradation causes the foam bar pad to develop long flat regions in its tubular shape which, in turn, accelerates the failure of the pad, rendering it useless for cushioning or supporting weight on the user's body. In time, the flattened regions of foam crack, ultimately separate, and split apart, causing a complete failure of the bar pad. A fabric covered bar pad may have a somewhat longer life cycle due to the foam being enclosed or covered, but this additional layer of material does not reduce the effects of repeated compression cycles, and the product still fails in the end.

Another problem with the linear extrusion process is that while it may be efficient, it creates a linear tube of uniform cross section that is mismatched both to the contours of the human body and to ultimate function of the pad in distributing the weight of the barbell evenly and comfortably on the body for greater control. The mismatch between the user's body and the linear shape of the bar pad results in the creation of pressure points along the length of the pad that pinch the pad between the user and the bar, distorting the shape of the pad. When this happens, the bar pad foam gets repeatedly compressed or point loaded in the same regions, accelerating the failure of the material and reducing its usefulness as a cushioning barrier.

OBJECTS AND SUMMARY OF THE INVENTION

It is, in general, an object of the invention to provide a new and improved pad that mounts on the bar of a barbell and spreads forces exerted by the bar over a larger area of the shoulders, neck, and/or chest of a person upon which the bar is resting.

Another object of the invention is to provide a pad of the above character which overcomes the limitations and disadvantages of barbell pads heretofore provided.

These and other objects are achieved in accordance with the invention by providing a pad that mounts on the bar of a barbell and has an elongated body of resilient, highly compressible injection molded EVA foam with an annular cross section, an inner surface that grips the bar and holds the pad in place on the bar, and an outer surface with an ogee curvature that conforms to the contour of the shoulders, neck, and/or chest of the person using the barbell.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a person holding a barbell having one embodiment of a pad incorporating the invention resting on his/her shoulders.

FIG. 2 is an isometric view of the barbell pad in the embodiment of FIG. 1.

FIG. 3 is a cross-sectional view taken along lines 3-3 of FIG. 2.

FIG. 4 is a cross-sectional view taken along lines 4-4 of FIG. 2.

FIG. 5 is a side elevational view, somewhat schematic, of the barbell pad in the embodiment of FIG. 1.

FIG. 6 is an isometric view of a person doing front knee bends or squats with the barbell in the embodiment of FIG. 1 resting against his/her chest and shoulders.

FIG. 7 is a side elevational view of another embodiment of a barbell pad according to the invention.

FIGS. 8 and 9 are cross-sectional views taken along lines 8-8 and 9-9 of FIG. 7.

FIG. 10 is a side elevational view of another embodiment of a barbell pad according to the invention.

FIG. 11 is a cross-sectional view taken along lines 11-11 of FIG. 10.

FIG. 12 is a cross-sectional view taken along lines 12-12 of FIG. 10.

DETAILED DESCRIPTION

In FIG. 1, barbell pad 16 is illustrated in conjunction with a barbell 17 having an elongated bar 18 with weight plates 19 removably mounted on opposite end portions of the bar.

As further illustrated in FIGS. 2-5, barbell pad 16 has an elongated body 21 of injection molded EVA foam which is mounted on the bar, with the bar passing through an axially extending opening 22 in the body. The pad has an annular cross section, with an inner diameter corresponding to the diameter of the bar and an outer diameter that varies along the length of the pad in accordance with the contours of the human body that the bar will rest against. In the embodiment illustrated, opening 22 has a straight cylindrical side wall 23, but it could have a different contour corresponding to the shape of another bar.

The outer surface 24 of the bar pad body has a cylindrical central section 26 of substantially uniform diameter, concavely curved sections 27, 27 that extend from opposite ends of the central section and increase in diameter toward the ends of the body, convexly curved sections 28, 28 that extend from the concavely curved sections and further increase in diameter toward the ends of the body, and rounded end sections 29, 29 which decrease in diameter between the outer ends of sections 28, 28 and the ends of the body. Concavely curved sections 27, 27 and convexly curved sections 28, 28 blend together smoothly and form ogee curvatures 31, 31 that closely match the contours of the shoulders, chest, and/or neck of the human body. The contours of the bar pad are symmetrical about the longitudinal axis of the bar pad body which is shown as being aligned with the x-axis in the drawings. The pad is also symmetrical about a central radial plane which is perpendicular to the longitudinal axis and coincides with the y-axis in the drawings.

Central section 26 extends between two radial planes A, only one of which can be seen in the portion of the pad shown in FIG. 5. These two planes are spaced equally from the central plane and are perpendicular to the longitudinal axis of the body. Concavely curved sections 27 extend from radial planes A to radial planes B which are also spaced equally from the central plane, and convexly curved sections 28 extend from radial planes B to a radial planes C which are likewise spaced equally from the central plane. End sections 29 extend from radial planes C to the outer ends of the pad.

A slit 32 extends the length of the body, opens through inner surface 23 and outer surface 24 on one side of the body, and permits the portions of the body on opposite sides of the split to separate and allow the bar to pass between them as the pad is being mounted on or removed from the bar. In this embodiment, the slit lies in an axial plane that intersects the axis of the body, and it opens through the outer surface along a straight line that extends from one end of the body to the other.

Unlike barbell pads of the prior art, the foam body of barbell pad 16 is made by an injection molding process in which granular ethylene vinyl acetate (EVA) and one or more foaming agents are heated under moderate pressure in a chemical reaction that cross links the mixture together into one stable material. The mold is preheated to a temperature on the order of 80° C., and a vacuum is created within the mold to facilitate flow throughout the cavity. The EVA and foaming agent(s) are injected into the preheated mold and then heated to a temperature on the order of 170° C. to bring about the reaction that cross links the mixture together and produces the foam. The cavity is smaller in size than the final product, which restricts the expansion of the foam and causes a large volume of small gas bubbles and microcells to form in a very confined space. When the mold is opened, the pad is allowed to expand, pop out of the cavity, and cool. As the pad cools, it contracts to its final size with a densely packed closed cell structure and a cellular volume that is not possible with traditional extruded foam processes. If desired, the pad can be cooled on a form which limits contraction and ensures more precise dimensions in the final product.

A preferred EVA foam material for the barbell pad is made from a blend of ethylene vinyl acetate (EVA), thermoplastic rubber (TPR), and calcium carbonate, with a blend of 22 percent EVA, 75 TPR, and 3 percent calcium carbonate giving particularly good results. This closed cell foam material yields a pad that exhibits minimal compression set and maintains proper form and function throughout its useable life. This allows significant compression during use, which spreads the force of the load over a larger area of the shoulders, neck, and/or chest, thereby reducing pressure and maximizing comfort. After the load is removed from the pad, the foam rebounds to its original shape, making it an ideal material for a barbell pad.

The resilient nature of the EVA foam blend gives the pad a springback property that causes the pad to close and clamp about the bar, with the inner surface 23 of the pad in gripping engagement with the bar. This, in combination with the shape or geometry of the pad, holds the pad tightly to the bar, prevents unwanted rotation between the pad and the bar, and avoids the need for secondary closures such as the cover and fasteners employed in other barbell pads.

The durable, closed cell nature of the EVA foam material allows the bar pad to be used without a protective cover, which means that it may come in contact with the skin. That, however, is not a problem because the EVA foam material is latex free and has a smooth surface that provides a comfortable interface when in contact with the skin. Because of the durable nature of the foam, the surface will remain smooth and easy to clean throughout the lifetime of the pad. The mechanical properties of the material are stable, and the material will not become sticky upon exposure to heat. The material is allergen free and moisture resistant.

The shape of the barbell pad is also significant to its function, comfort, and control in relation to the human body during exercise and use of the pad. The unique ogee surface contours are specifically selected to support and distribute the weight of a loaded barbell evenly across the human body during exercise and use and to eliminate pressure points caused by the linear nature of barbell pads heretofore provided. In addition, the contour of the bar pad improves control because the curvature of the pad corresponds to the natural curvature of the body, thus creating an improved relationship between the user, bar pad, and barbell. The ogee curvature allows the bar pad to transition around key areas and pressure points of the trapezius, deltoids, neck, spine, chest cavity, and collar bones, thereby increasing comfort and control.

In FIG. 1, the barbell 17 is shown resting on the tops of the shoulders on the back side of the user's neck as it might, for example, be positioned for doing exercises such as knee bends or squats. As can be seen in this figure, the ergonometric curvature 33 formed by ogee curves 31, 31 conforms closely to the curvature of the neck and shoulders, and the rounded end sections 29, 29 provide additional comfort for the shoulders.

FIG. 6 shows a person doing front knee bends or squats with the barbell 17 resting against his/her upper chest and shoulders. Here, the ergonometric curvature 33 avoids the neck or throat, and the rounded end sections 29, 29 provide additional comfort for the shoulders.

With the injection molding process, it is also possible to create surface textures on the foam body, and the embodiment of FIGS. 2-5, for example, has a plurality of longitudinally extending slots 36 in the outer surface of the body, lines 37 encircling the body near the base of end sections 29, and a plurality of concentric, segmented rings 38 on the outer ends of the end sections.

FIGS. 7-9 and 10-12 show additional embodiments of the barbell pad. These embodiments are generally similar to the embodiment of FIGS. 2-5, and corresponding elements are designated by like reference numerals in the three embodiments.

In the embodiment of FIGS. 7-9, the pad differs from the pad in the embodiment of FIGS. 2-5 in that it has a stepped slit rather than a straight one, and it has a smooth outer surface with no slots or other textured features. The stepped slit has a central section 41 and end sections 42, 42 which open through the outer surface of the body along laterally offset parallel lines, with short sections 43, 43 providing a smooth transition between the others. Central section 41 and end sections 42, 42 lie in axial planes which intersect at the axis of the body and are offset from each other by an angle on the order of 40 degrees.

The embodiment of FIGS. 10-12 is similar to the embodiment of FIGS. 7-9 except that slit sections 41 and 42, 42 lie in planes that are spaced from and parallel to each other and to the axis of the body. The spacing between the two planes is slightly less than the diameter of opening 22, and the planes are almost tangential to the upper and lower sides of the opening, as viewed in these figures.

The invention has a number of important features and advantages. The pad spreads forces exerted by a barbell over a larger area of a person's body, providing greater comfort and control than the straight tubular pads heretofore provided. The ogee curvature conforms closely to the contours of the body, and the durability and resiliency of the closed cell foam material yield a pad that exhibits minimal compression set and maintains proper form and function throughout its useable life. The injection molding process produces a cross-linked foam with a densely packed closed cell structure and a cellular volume that is not possible with traditional extruded foam processes.

It is apparent from the foregoing that a new and improved barbell pad has been provided. While only certain presently preferred embodiments have been described in detail, as will be apparent to those familiar with the art, certain changes and modifications can be made without departing from the scope of the invention as defined by the following claims. 

1. A pad that mounts on the bar of a barbell and spreads forces exerted by the bar over a larger area of the shoulders, neck, and/or chest of a person using the barbell, comprising: an elongated body of resilient, highly compressible injection molded EVA foam having an annular cross section, an inner surface that grips the bar and holds the pad in place on the bar, and an outer surface with an ogee curvature that conforms to the contour of the shoulders, neck, and/or chest of the person using the barbell.
 2. The pad of claim 1 wherein the EVA foam is a blend of ethylene vinyl acetate, thermoplastic rubber, and calcium carbonate.
 3. The pad of claim 2 wherein the blend consists of 22 percent ethylene vinyl acetate, 75 percent thermoplastic rubber, and 3 percent calcium carbonate.
 4. The pad of claim 1 wherein the foam body is manufactured by heating a mixture of granular ethylene vinyl acetate and foaming agent in a mold to form a large volume of small gas bubbles and microcells in a confined space, opening the mold, and allowing the body to pop out, expand, and cool to form a densely packed closed cell structure.
 5. The pad of claim 1 wherein the elongated body has a central section, concavely curved sections extending from opposite ends of the central section and increasing in diameter toward the ends of the body, and convexly curved sections extending from the concavely curved sections and further increasing in diameter toward the ends of the body, with the concavely curved sections and the convexly curved sections forming the ogee curvature that conforms to the contour of the shoulders, neck, and/or chest of the person using the barbell.
 6. The pad of claim 5 wherein end portions of the body are inwardly curved and decrease in diameter between the convexly curved sections and the ends of the body.
 7. The pad of claim 1 including a split that extends the length of the body, opens through the inner and outer surfaces on one side of the body, and permits portions of the body on opposite sides of the split to separate and allow the bar to pass between them as the pad is being mounted on or removed from the bar.
 8. The pad of claim 7 wherein the split lies in an axial plane that intersects the axis of the annular body.
 9. The pad of claim 7 wherein the slit has a central section which lies in a first plane and end sections which lie in a second plane that is spaced from the first plane.
 10. The pad of claim 9 wherein the first and second planes are parallel to each other and to the axis of the annular body.
 11. The pad of claim 7 wherein the pad is maintained in position on the bar by the resiliency of the injection molded foam body clamping the pad to the bar.
 12. A pad that mounts on the bar of a barbell for spreading forces exerted by the bar over a larger area of the shoulders, neck, and/or chest of a person using the barbell, comprising: an elongated body of resilient, highly compressible injection molded EVA foam having an axially extending opening in which the bar is received and an outer contour that conforms to the shoulders, neck, and/or chest of the person.
 13. The pad of claim 12 wherein the EVA foam is a blend of ethylene vinyl acetate, thermoplastic rubber, and calcium carbonate.
 14. The pad of claim 13 wherein the blend consists of 22 percent ethylene vinyl acetate, 75 percent thermoplastic rubber, and 3 percent calcium carbonate.
 15. The pad of claim 12 wherein the foam body is manufactured by heating a mixture of granular ethylene vinyl acetate and foaming agent in a mold to form a large volume of small gas bubbles and microcells in a confined space, opening the mold, and allowing the body to pop out, expand, and cool to form a densely packed closed cell structure.
 16. The pad of claim 12 including a slit that extends the length of the body and allows portions of the body on opposite sides of the slit to separate and allow the bar to pass into and out of the opening.
 17. The pad of claim 16 wherein the pad is maintained in position on the bar by the resiliency of the injection molded foam body clamping the pad to the bar.
 18. A pad that mounts on the bar of a barbell and spreads forces exerted by the bar over a larger area of the shoulders, neck, and/or chest of a person exercising with the barbell, comprising: an elongated body of resilient, highly compressible foam and annular cross section having concavely curved sections extending from opposite ends of a central section and increasing in diameter toward the ends of the body, convexly curved sections extending from the concavely curved sections and further increasing in diameter toward the ends of the body, with the concavely curved sections and the convexly curved sections forming ogee curves that conform to the contour of the shoulders, neck, and/or chest of the person exercising with the barbell, and inwardly curved end sections that decrease in diameter between the ogee curves and the ends of the body.
 19. The pad of claim 18 including a slit that extends the length of the body and permits portions of the body on opposite sides of the slit to separate and allow the bar to pass between them as the pad is being mounted on or removed from the bar.
 20. The pad of claim 19 wherein the pad is maintained in position on the bar by the resiliency of the foam clamping the body of the pad to the bar. 